The Federal Government has refused entry to more than 500 Syrian and Iraqi refugees over the last year because they failed security checks.

Immigration Minister Peter Dutton said the Government used intelligence from security allies, including the United States, to make the security assessments.

Some of those rejected were part of 12,000 Syrian refugees being resettled in Australia.

Mr Dutton called the number of refusals "startling" and said it justified the Coalition's decision to put Syrian refugees through stringent security checks.

"The Labor Party had advocated we should bring these people in very quickly and if we had done that we wouldn't have detected these people and I think there would have been significant consequences in our own country," Mr Dutton said.

"I think the tragic events in London and elsewhere demonstrate the Government's approach was prudent.

"There are people we've excluded on national security grounds that we have not brought to our country and we never will."

Mr Dutton said the Government's approach could give the Australian community confidence that the refugees who have been accepted would not pose a threat.

"We have brought people here who have passed security checks, and they will contribute significantly to Australian society," he said.

"They will be good Australians they will work hard and they will educate our children — they are the migrants we want coming to our country."

The Minister did not provide detailed information about the screening process, but said they drew on intelligence sources and law enforcement agencies from several countries.

"The United States has significant intelligence holdings in relation to people coming out of the Middle East. There's a lot of work done with the Brits and Canadians as well but there are other partners we've worked with as well," he said.

"We have been stringent, we've been deliberately methodical in the way we've conducted because we don't want people coming into our country who pose a threat I want people here who are escaping violence not bringing violence here."